Bottom Line:
Much of the work on face-selective neural activity has focused on posterior, ventral areas of the human and non-human primate brain.We examined a region at the junction of the right inferior frontal sulcus and the precentral sulcus (right inferior frontal junction or rIFJ) that responds more to faces than to several other object categories.We speculate on this role with reference to emotion perception, gaze perception, and to behavioral relevance more generally.

Affiliation: School of Psychology, Wales Institute of Cognitive Neuroscience, Bangor University Gwynedd, UK.

ABSTRACTMuch of the work on face-selective neural activity has focused on posterior, ventral areas of the human and non-human primate brain. However, electrophysiological and fMRI studies have identified face responses in the prefrontal cortex. Here we used fMRI to characterize these responses in the human prefrontal cortex compared with face selectivity in posterior ventral region. We examined a region at the junction of the right inferior frontal sulcus and the precentral sulcus (right inferior frontal junction or rIFJ) that responds more to faces than to several other object categories. We find that the rIFJ and the right fusiform face area (rFFA) are broadly similar in their responses to whole faces, headless bodies, tools, and scenes. Strikingly, however, while the rFFA preferentially responds to the whole face, the rIFJ response to faces appears to be driven primarily by the eyes. This dissociation provides clues to the functional role of the rIFJ face response. We speculate on this role with reference to emotion perception, gaze perception, and to behavioral relevance more generally.

Figure 1: Panel (A) shows activations in the rIFJ and the rFFA during a 1-back task. Panel (B) shows activations in the rIFJ during passive viewing. Panel (C) shows the activation overlap in the rIFJ for both tasks (green for 1-back, yellow for passive viewing). All regions are defined by the contrast of faces–tools (p < 0.0001, t > 5.30). For comparison, panel (D) shows the FFA in the 1-back task (left), in the passive task (center), and the overlap between these activations (right). All regions are defined by the contrast of faces–tools (p < 0.0005, t > 3.50). Axial slices at Z = −18.

Mentions:
In the free-viewing task group, 10 out of 10 participants showed significant activation in the rIFJ, and 8 out of 10 showed significant activation in the rFFA. In the 1-back task group, all participants showed significant activation in both the rIFJ and rFFA. To facilitate comparison between the two groups, analyses were performed on those eight participants in the free-viewing task group who showed significant activation in both regions, and on 8 out of 10 participants who were selected randomly from the 1-back task group. The mean Talairach coordinates (with standard deviation, SD) of the peak location of the ROIs across participants were: 1-back group: rIFJ [48(6), 8(7), 33(5)]; rFFA [38(3), −45(7), −17(4)]; free-viewing group: rIFJ [43(7), 11(9), 35(6)]; rFFA [38(3), −48(8), −14(4); see Figure 1].

Figure 1: Panel (A) shows activations in the rIFJ and the rFFA during a 1-back task. Panel (B) shows activations in the rIFJ during passive viewing. Panel (C) shows the activation overlap in the rIFJ for both tasks (green for 1-back, yellow for passive viewing). All regions are defined by the contrast of faces–tools (p < 0.0001, t > 5.30). For comparison, panel (D) shows the FFA in the 1-back task (left), in the passive task (center), and the overlap between these activations (right). All regions are defined by the contrast of faces–tools (p < 0.0005, t > 3.50). Axial slices at Z = −18.

Mentions:
In the free-viewing task group, 10 out of 10 participants showed significant activation in the rIFJ, and 8 out of 10 showed significant activation in the rFFA. In the 1-back task group, all participants showed significant activation in both the rIFJ and rFFA. To facilitate comparison between the two groups, analyses were performed on those eight participants in the free-viewing task group who showed significant activation in both regions, and on 8 out of 10 participants who were selected randomly from the 1-back task group. The mean Talairach coordinates (with standard deviation, SD) of the peak location of the ROIs across participants were: 1-back group: rIFJ [48(6), 8(7), 33(5)]; rFFA [38(3), −45(7), −17(4)]; free-viewing group: rIFJ [43(7), 11(9), 35(6)]; rFFA [38(3), −48(8), −14(4); see Figure 1].

Bottom Line:
Much of the work on face-selective neural activity has focused on posterior, ventral areas of the human and non-human primate brain.We examined a region at the junction of the right inferior frontal sulcus and the precentral sulcus (right inferior frontal junction or rIFJ) that responds more to faces than to several other object categories.We speculate on this role with reference to emotion perception, gaze perception, and to behavioral relevance more generally.

Affiliation:
School of Psychology, Wales Institute of Cognitive Neuroscience, Bangor University Gwynedd, UK.

ABSTRACTMuch of the work on face-selective neural activity has focused on posterior, ventral areas of the human and non-human primate brain. However, electrophysiological and fMRI studies have identified face responses in the prefrontal cortex. Here we used fMRI to characterize these responses in the human prefrontal cortex compared with face selectivity in posterior ventral region. We examined a region at the junction of the right inferior frontal sulcus and the precentral sulcus (right inferior frontal junction or rIFJ) that responds more to faces than to several other object categories. We find that the rIFJ and the right fusiform face area (rFFA) are broadly similar in their responses to whole faces, headless bodies, tools, and scenes. Strikingly, however, while the rFFA preferentially responds to the whole face, the rIFJ response to faces appears to be driven primarily by the eyes. This dissociation provides clues to the functional role of the rIFJ face response. We speculate on this role with reference to emotion perception, gaze perception, and to behavioral relevance more generally.